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Source: Official Guide Revised GRE 1st Ed. Part 6; Set 1; #5


r, s, and t are three consecutive odd

r, s, and t are three consecutive odd integers such that r < s < t. Quantity A r+s+1 Quantity B s+t-1 Quantity A is greater., Quantity B is greater., The two quantities are equal., The relationship cannot be determined from the information given.

3 Explanations


Question: what if r, s and t are negative numbers? such that -7 < -5 < -3.
Then the above would not be correct..? or would it?

Sep 8, 2015 • Comment

Cydney Seigerman, Magoosh Tutor

Let's plug in those values for r, s, and t and find out!

Quantity A: r + s + 1 = -7 + (-5) + 1 = -11
Quantity B: s + t - 1 = -5 + (-3) - 1 = -9

As -11 < -9, Quantity A is less than Quantity B. So, our answer is still B, Quantity B is greater :)

Oct 10, 2015 • Reply


Yosef Lewis

Another method is, after eliminating the s (just as instructed above) you can substitute t with r+4. We know this works, because we are instructed that the three integers are consecutive, odd, integers, so s=r+2 and t=r+4.

Since we have already eliminated the s we are now left with r+1 on the A column, and r+4-1, which simplifies to r+3, on the B column.

r+1 will always be less than r+3, so B is our answer. :)

Apr 10, 2014 • Comment

Lucas Fink

Very true. :-) That gets to the same basic idea that Chris shows in the video, just via a slightly more abstract way of thinking—the concrete numbers just illustrate why t = r + 4. Well done!

Apr 11, 2014 • Reply


Chris Lele

Oct 6, 2012 • Comment

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